1. Field of the Invention
The invention relates to a digital signal transmission system, and in particular is directed to a system for transmitting digital information signals through a transmission medium, such as magnetic tape and microwave line, which is subjected to disturbances causing burst errors, and for enabling correction of the errors which occur in the received digital signal.
2. Description of the Prior Art
Recently, there is proposed to record a digital information signal, such as audio PCM signal, on a magnetic tape by using video tape recorder. However, it is well known that drop-outs causing a burst error frequently occur in the digital signal reproduced from the tape. There are provided several types of transmission system to correct such a burst error as appearing in the reproduced PCM signal. One of the systems is shown in U.S. Pat. No. 3,409,875, in which the PCM signal is transmitted through two lines, one of which includes a predetermined delay. In the receiving side, the outputs of the lines are applied to an output device through a switch controlled by an error responsive device, which is responsive to unequal signals at the outputs of the lines, so that upon detection of the unequal signals the switch is connected to the line having a delay for a predetermined time. Thus, the system can correct the burst errors appearing in the line. However, it is necessary in the above system to provide the two lines for transmission of the same signal. In other words, the capacity of the transmission medium is needed double the usual one.